@article{21844,
  abstract     = {Little red dots (LRDs) are a newly identified class of broad-line active galactic nuclei (AGNs) with a distinctive V-shaped spectrum characterized by red optical and blue UV continuum emission. Their high abundance at redshifts of z ∼ 6–8 and decline at lower redshifts suggest a transient origin. We propose that the spectral shape of LRDs originates from compact binary black hole systems, in which each black hole is surrounded by a mini-disk and embedded within a larger circumbinary disk. With a binary separation of ≲103 Schwarzschild radii, the Wien tail of a T ≃ 5000 K blackbody spectrum at the inner edge of the circumbinary disk produces the red optical emission, while the mini-disks power the UV continuum. Binary torques carve out a gap between the circumbinary disk and the mini-disks, setting the turnover wavelength of the V-shaped spectrum around the Balmer limit. This scenario naturally reproduces LRD spectra requiring only modest dust attenuation (AV ≲ 1 mag), resolving overestimated luminosities for LRDs in previous studies and alleviating a tension with the so-called Sołtan argument. This model predicts distinct spectral evolution as the binary orbit decays through binary disk interactions and gravitational-wave (GW) emission, linking early-stage “proto-LRD” binaries to the broader AGN population and late-stage “LRD descendants” to coalescing binaries detectable in GW experiments.},
  author       = {Inayoshi, Kohei and Shangguan, Jinyi and Chen, Xian and Ho, Luis C. and Haiman, Zoltán},
  issn         = {1538-4357},
  journal      = {The Astrophysical Journal},
  number       = {1},
  publisher    = {IOP Publishing},
  title        = {{The emergence of Little Red Dots from binary massive black holes}},
  doi          = {10.3847/1538-4357/ae548d},
  volume       = {1002},
  year         = {2026},
}